added automatic selection of GOES satellite and data type based on input time
typo fix
fixes to the call to _get_goes_sat_num_and_data_type.
Simplified code by separating GOES operational dates and data formats into two dictionaries. Added date and data format source to docstring.
Merge pull request #675 from aringlis/goes

GOES lightcurve now knows which satellite to download from and the data type